New tub install questions

I have been working through remodeling a galley style bathroom built in 1979.

I removed the cast iron tub and will be replacing it with another tub (maybe acrylic).
I failed to measure the previous tub and now I see 30" or 32" are the common sizes. Below is a picture of old drain assembly which is about 15" from the bare studs. I assume that means I would need to order a 30" tub? I've also included a picture of the tub in our spare bath which I assume is the same size as the one I removed.

Second question. Some tub specifications state above floor drain. I assume since my old drain is flush with the floor it is not an above floor drain?

Buy a new tub, and a new drain for the tub. What you had was a Kohler Villager cast iron tub. Either K-715 or K-716. That tub was 60x30x14
Standard size tubs come in 60" length and widths of 30 and 32
The toilet from center to edge should be 15". That's why often the rough for the toilet was 45" from the side wall. 30" for the tub, and 15" to center for the toilet.

Kohler makes some of the best cast iron tubs out there. And I've been installing some of their new acrylic tubs too. Very nice
As I get older, I'm liking the acrylic more and more.

Thanks for the response Terry. I measured the distance to the closet flange and it is 47" to the center from the bare studs.

I'm leaning toward the Sterling by Kohler All Pro 60" x 30" Bathtub. Does anyone have any experience with that tub? I have no preference other than I can buy it locally. It does seem awfully cheap ~$200. I want a solid quality tub and price less than $600 is an option. Any recommendations? I don't think I want a steel tub and cast it too heavy / difficult for me to install.

We decided on the Sterling by Kohler All Pro 60" x 30" Bathtub. And I have a some questions. While I'm waiting for it to arrive I wanted to make sure the plumbing and the rough in was good to go. In looking at the tub's instructions...

1. The 61041110 installation instructions shows a dimension requirement from the back studs to the drain cutout as 14". I measure more like 14-3/4" (see pictures in my previous post #1). Do I need to cut out the p-trap and try to move it closer to the back wall? It seems like the drain would not be a problem to align but the centerline of the overflow would be a problem?
2. The long axis of the tub calls for 60-1/4"MAX rough in and the opening I have is 60-3/8. Can I split the difference?, shim?, justify to one side?

3/4" is a ways to try to swing a drain over a trap. That's why I tend to cut those off and start over.
I doubt you will need to shim the walls. Are you using the wall panels, or installing backerboard and tiling?
Those tubs come with a felt pad to put underneath. However, I would check your floor for level, and it it's not, you may want to shim and use something else under the tub like mortar for support.
It's it's level, then the felt pad is fine.

The old waste and overflow is in place as an example, I will buy a new one for the install.
The drain trap will not move more than 3/8â€. So, It looks like a will have to move the trap over 3/4" toward the back wall.
I was thinking I would cut back some more floor (red line) then cut the straight pipe (blue line) that attaches to the trap / vent and then glue some sort of union to attach the a new trap to?

I'm not sure if this type of fitting (on the left) exists to attach to the straight pipe that goes to the vent?

<edit>
I will be using backer board and tile.
I plan to put down some thinset mortar under the tub.
Thx, Wayne

Why's that? Are you planning on using Ardex X32? That would be the only one thin-set I would use.

I would use any brand of Mortar Mix but only that one specific thin-set. X32 cost about 5 times the price of Mortar Mix.

I would re-think your thin-set angle for this install...

Click to expand...

Hi John,

Thanks for the warning. I must have read it somewhere on the internet to use thinset, and I would have it on hand for the tile job. Now that you raised the issue, would it be okay to use Quikrete sand mix concrete from HD?

For your previous questions. I hadn't planned on blocking behind the wall Hardi. I don't think I have any larger than normal spans between studs (15"?). On the subfloor I plan to thinset/screw 1/4" Hardi including the tub area so the tub will sit on Hardi.
Thanks, Wayne

The tub showed up, but unfortunately it was damaged in shipping. One of the feet that it sits on is broken and I don't trust it to not crack eventually in that location. While I wait for the replacement tub I can work on getting the rough-in ready for the new tub. The tub is about 5/8" smaller than the rough in. I'm wondering how / if I need to address the problem?
1. I assume I should fir one side or the other out to meet the tub / flange?
2. Does it matter which side? I was thinking the drain / left side.

I came up with a couple more questions to add to the above previous two.

3. Is it a big deal to have misalignment of the tub spout and shower head with the waste and overflow or is the 1/2-3/4" offset okay? See the plumb line from the spot position.
4. Does anyone have an opinion on the WATCO FLEX916 as an option to connect the waste/overflow? The only issue may be connecting the PVC to the ABS? Can I use a slip joint (current ABS if threaded) or use pvc/abs glue?

Functionally, on the alignment, it does not matter at that level, but aesthetically, you may or may not care. FWIW, mine is slightly offset, and it does not bother me, but then, it would be a major issue with some people. I wish the plumber had done a little better job, but hey, it works.

I'll second Terry's comment on the galvanized pipe there...you really want to get rid of any you have access to right now. And, if this is also going to have a showerhead, you'll need to update the valve (and it's not a bad idea to do it now since it's likely to be covered up again for maybe decades before you want to remodel). Finding repair parts for older valves is sometimes easy, but not always. And, if it is a shower, code would require you to change it.

If you're tiling the walls, regarding the tiling flange, you have two options (depending on the size of the tile - small ones, your options are fewer): if at least 50% of the tile will be on the backerboard (cbu), then you can stop the cbu at the top of the tiling flange; if it won't, then you need to either notch the studs to allow the flange to be flush with the rest of the studs, or you need to fir out the studs to make the flange/wall joint even, so you won't be trying to make the cbu bow out over that lip. Then, you have the issue of how to do moisture control, which is a whole other topic.

If your studs are not nice and plumb and in plane (one not higher or lower than the rest), then you could sister them with new and make sure they are nice and flat. Check the corners, too - true 90-degree ones are nicer, especially if you are going with a surround rather than tiling.

Consider using engineered expansion joints for the tub/wall and wall/wall joints. Then, no caulk is needed, ever. And, they can help hide a funky cut or an out of plumb wall since the straight edge of the profile fools the eye.

Compression tubular fittings are only supposed to be used where you have access, and you probably will not underneath the tub. Some places will not approve of transition cement...best to get a drain that matches what you've already got in the floor, or use the shielded coupler (but that requires access to tighten the bolts).

As Terry mentioned, shimming out the walls can present a challenge on finishing them to look nice on the transition to the rest of the room, so that needs some thought first.